Frost dates for Casa Grande National Monument, AZ
At Casa Grande National Monument, the median last spring frost (32°F) is Feb 17 and the median first fall frost is Nov 29, for a typical growing season of 284 days. For a 90% chance that the last frost has passed, wait until Mar 8. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 17Last spring frost (median)50% chance of 32°F after this date
- Mar 8Safer planting date10% chance of 32°F after this date
- Nov 29First fall frost (median)50% chance of 32°F by this date
- 284 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Feb 16 | Mar 8 | Apr 5 |
| 32°F | Jan 22 | Feb 17 | Mar 8 |
| 28°F | Dec 26 | Jan 26 | Feb 23 |
| 24°F | Dec 13 | Jan 7 | Feb 4 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Nov 4 | Nov 19 | Dec 3 |
| 32°F | Nov 12 | Nov 29 | Dec 15 |
| 28°F | Nov 23 | Dec 12 | Jan 6 |
| 24°F | Dec 2 | Dec 28 | Jan 24 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 222 days | 251 days | 277 days |
| 32°F | 257 days | 284 days | 314 days |
| 28°F | 288 days | 322 days | 355 days |
| 24°F | 329 days | 363 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 95% |
| 24°F | 57% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85128 | 9a | 20 to 25°F | 4 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00021314, at 32.9947, -111.5367, elevation 432 m (1,419 ft).
- Data quality: Representative (10+ years), 26 years of freeze data.
- Average days per year at or below 32°F: 29.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Florence (15 km)
- Casa Grande (20 km)
- Robson Rch (22 km)
- Eloy 4 NE (24 km)
- Chandler Heights (27 km)
- Arizona City (33 km)
- Picacho 8 SE (41 km)
- Maricopa 4 N (48 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.